Send the rest at once after the first passes, and resume a stored gate (hq ADR 0353)

A release now sends every other machine in one step once its first machine
passed, each judged by its own gate; a failing one is put back without
stopping the others, a silent one is left. A send is kept before it is made,
and a machine already sent what a gate is for is not sent again: the gate
counts from that send and takes over another walk's readings of the same
build there.

cmd/mesh-controller/walk_said.go

@@ -177,6 +177,12 @@ func walkReached(p inventory.Plan, running func(string) []string) map[string][]s
 			reached = appendNew(reached, r.Gate.Machines...)
 			carried(r.Gate)
 		}
+		for _, g := range r.Gates {
+			if g != nil && !g.Pending {
+				reached = appendNew(reached, g.Machines...)
+				carried(g)
+			}
+		}
 		for _, tier := range p.Tiers {
 			for _, m := range tier {
 				for _, n := range running(m) {